Food spoilageFood spoilage

Strategies of prevention and new trends for preservation

Microflora affecting food shelf-life

GIOACCHINO dell'AQUILA – MODERN MICROBIOLOGY COURSEFOOD ENGINEERING MASTER DEGREE – ISTANBUL AYDIN UNIVERSITY, TURKEY

Precautions and measures adopted in production, processing, storage and distribution in order to obtain a safe, stable and tasty product suitable for

human consumption

Inactivate microrganismsProcessing managementWell tested preservation procedures

Prevent multiplicationRapid handling and movementAppropriate storage and distribution

Avoid contaminationAccettable sanitary practicesGood manifacturing practices

Pathogens - Food SafetyPathogens - Food Safety hygiene, contamination, cooking

Foodborne diseases

Probiotics – Food TechnologyProbiotics – Food TechnologyImprovement of nourishing quality

Production of selfpreserving products

Spoilage - Food QualitySpoilage - Food Quality shelf-life is affected

loss of money unnourishing product

customer dissatisfaction

Why keeping food from Why keeping food from

spoilage?spoilage?

Deterioration leads to food wasting

Contaminated food could be poisoning

Money save keeping food from spoilage

Unspoiled food retains also nourishing quality

Ensuring availability of food

Where are microrganisms?Where are microrganisms?

- Soil and water - Plants and plant products

- Air and dust - Animal hides

- Gastro intestinal tract of animals and humans - Food handlers

- Utensils and processing equipment

How does spoilage How does spoilage

manifest?manifest?

Visible growth – moulds produce large pigmented colonies (visible bacterial and yeast colonies are less common) Gas production (flat-sour spoilage vs swelling)Slime Diffusable pigment and enzymes produce softening and rotting (proteolysis) Off-odours Off-flavours

Microrganisms in foodMicrorganisms in food

BACTERIABACTERIA

PathogensPathogens

SpoilageSpoilage

ProbioticProbiotic

FUNGIFUNGI

YeastsYeasts

MoldsMolds

Manifacturing Manifacturing

intendedintended

VIRUSES

PARASITESPARASITES – Micro and macrorganism

BacteriaBacteriaGram +ve

Micrococcus; Brocothrix (non-spore formers)

Bacillus; Clostridium (spore formers)

Lactobacillus; Streptococcus, Leuconostoc (Lactic Acid Bacteria)

Gram -vePseudomonas, Enterobacteria (Salmonella, Escherichia, Erwinia)

YeastsYeasts Candida, Saccharomyces, Zygosaccharomyces

MouldsMoulds Aspergillus, Zygomycetes, Penicillium

Factors affecting spoilage Factors affecting spoilage

microfloramicrofloraInitial concentration

Food texture, nutrient composition

Acidity

Time temperature ratio

Redox potential

Water activity

There are a wide range of metabolites produced during microbial spoilage including:

• Alcohols • Sulphur compounds • Ketones • Hydrocarbons • Fluorescent pigments • Organic acids • Esters • Carbonyls • Diamines

Food categoriesFood categories

Different food categories present several inhibition characteristics

Cereals and bakeryDairy products

VegetablesFruit and Juices

Fresh meat / Processed meatFresh fish / Processed fish

Prevention of spoilagePrevention of spoilage

Managing temperature

Managing water activity

Managing oxygen presence

Managing food formulation

Accurate choice of processing technology

Antimicrobial compounds

Managing temperatureManaging temperature

Inadequate processing results in spoilage by thermoduric and mesophillic spore forming bacteria

Heat processing - Thermodurics: Clostridium, Bacillus, spores Pasteurisation - Thermodurics: Streptococcus, Lactobacillus,

spores Chilled Storage - Psychrotrophs: Pseudomonas,

Enterobacteriaceae, LAB, Micrococcus, Flavobacterium Most yeasts: Candida, Rhodotolura, Torulopsis

Most moulds Frozen Storage - None grow, but Gram-positives and spores

survive

Managing water activityManaging water activity

Dried Food - Aw 0.6 Osmophilic yeasts and moulds Saccharomyces, Aspergillus

Intermediate Moisture Food - Aw <0.85Osmophilic yeasts and moulds, Staphylococcus

Salt - Osmophiles, Micrococcus, Staphylococcus

Sugar - Osmophiles

Managing oxygen presenceManaging oxygen presence

Vacuum packing – Anaerobes, MicroaerophilesClostridium, Enterobacteraceae, LAB,

Streptococcus, Bacillus;Some yeasts

Carbon dioxide - Lactobacillus

Managing food compositionManaging food composition

Preservatives such as benzoate, sorbate, nitrites/nitrates, sulphure dioxide, chlorine, alcohol

as far as they are effectivedo not avoid the growth of yeasts

(e.g. Zygosaccharomyces bailii, Z. bysporus), Pseudomonas fragi

Saccharomyces cerevisiae, species of Escherichia coli and

Lactobacillus acidophilus

TRIAS MANSILLA, R; (2008). Lactic acid bacteria as bioprotective agents against

food borne pathogens and spoilage microrganisms in fresh fruit and vegetables

Choice of processing Choice of processing

technologytechnologyThermal processing

Water activity reduction Osmotic pressure

Addition of preservativesAnaerobiosis

RadiationControlled atmosphere

Asepsis Hurdles technique

High-pressureHigh-pressureLeuconostoc mesenteroides has been evaluated in mango juice

processed at 250 - 550 Mpa with an hold time 0 - 60 min at 20 – 25 °C.

It is one of the most resistant spoilage bacteria;

its complete destruction was achieved by a 5 min treatment at 400 MPa.

For pathogenic Escherichia coli A 6-log reduction was observed at 400 MPa when treated for 10 min

(at 500 and 550 MPa there were no survivors after the 1 min).

Results showed that these processes were satisfactory because no further growth was observed during the entire storage time.

HIREMATH, ND; RAMASWAMY, HS; (2011). High-pressure destruction kinetics

of spoilage and pathogenic microorganisms in mango juice

Pulsed Electric FieldPulsed Electric Field

Researchers at ARS/USDA (Agriculture Research Service / United States Department of Agriculture)

Demonstrated that

PEF treatment on salad dressings and apple juiceIs effective on Lactobacillus plantarium.

If additioned with mild heat treatment the shelf-life and sensory characteristics of food are retained for 470 days at room temperature

McGINNIS, L; (2006). Non thermal processing is heating up. ARS, United States

Department of Agriculture

RAYBAUDI-MASSILIA, RM; MOSQUEDA-MELGAR, J; SOLIVA-FORTUNY, R;

MARTIN-BELLOSO, O; (2009). Control of Pathogenic and Spoilage Microorganisms in

Fresh-cut Fruits and Fruit Juices by Traditional and Alternative Natural Antimicrobials

Log of CFU/g of standard plate count (SPC) values recorded on minced meat samples after 58°C/6 and 24 hs of essential oil addition

NUNES BARBOSA, L, et al.;

(2009). Essential Oils Against

Foodborne Pathogens and

Spoilage Bacteria in Minced Meat

Log of CFU/g for psychrotrophic microorganism values recorded on minced meat samples after 58°C/24 h of essential oil addition.

NUNES BARBOSA, L, et al.;

(2009). Essential Oils Against

Foodborne Pathogens and

Spoilage Bacteria in Minced

Meat

MUNDO, MA; PADILLA-ZAKOUR, OI; WOROBO, RW; (2004). Growth inhibition of

foodborne pathogens and food spoilage organisms by select raw honeys

Edible films made from spinach or apple enriched with EOs (carvacrol, citral,

cynnamaldehyde)

Are effective against

E. coli, Salmonella, Listeria

The efficacy is enhanced by the

“antimicrobial vapor-phase”

MCHUGH, TH; WEN-XIAN DU,

FRIEDMAN, M; (2008). For

tomorrow's salads: plants extracts to

conquer microbes.

Researchers measure the widht of the clear agar zone around the enriched EOs films (top) as a value of the repellent action of antimicrobial.

(Escherichia coli O157:H7)

What would be the strategy to ensure What would be the strategy to ensure

both aboth a

trustfull, stable and palatable food trustfull, stable and palatable food

able to supply the market needs?able to supply the market needs?

ReferencesPARFITT, J; BARTHEL, MACNAUGHTON, S; (2010). Food waste within food

supply-chain: quantification and potential change to 2050.

SINGLETON, I; New Castle University (2011). Ozone reduces fungal spoilage of

fruit and vegetables.

NUNES BARBOSA, L, et al.; (2009). Essential Oils Against Foodborne Pathogens

and Spoilage Bacteria in Minced Meat

SHERMAN, P; BILLING, J; (1999). Darwinian gastronomy: Why we use spices

ELLIN DOYL E, M; (2007). Microbial food spoilage. Losses and control strategies

ELGAYYAR, M, et al; (2001). Antinmicrobical activity of essential oils against

selected pathogenic and saprophitic microorganisms.

KISKO', G; ROLLER, S; (2005). Carvacrol and p-cymene inactivate Escherichia

coli O157:H7 in apple juice.

MUNDO, MA; PADILLA-ZAKOUR, OI; WOROBO, RW; (2004). Growth inhibition

of foodborne pathogens and food spoilage organisms by select raw honeys

MCHUGH, TH; WEN-XIAN DU, FRIEDMAN, M; (2008). For tomorrow's salads:

plants extracts to conquer microbes.

HIREMATH, ND; RAMASWAMY, HS; (2011). High-pressure destruction kinetics

of spoilage and pathogenic microorganisms in mango juice

RAYBAUDI-MASSILIA, RM; MOSQUEDA-MELGAR, J; SOLIVA-FORTUNY, R;

MARTIN-BELLOSO, O; (2009). Control of Pathogenic and Spoilage

Microorganisms in Fresh-cut Fruits and Fruit Juices by Traditional and Alternative

Natural Antimicrobials

Web referencesInteractive Agricultural Ecological Atlas of Russia and Neighboring Countries. Economic Plants and their Diseases, Pests and Weeds (2008).

Agriculture Research Service, United States Department of AgricultureCenters for Dieseases Control and PreventionSociety for General MicrobiologyAmerican Council for Consumers interestsFood Technology IntelligenceFresh PlazaEurekAlert!ScirusSciencedirectSpringer

Thank you for your attention!Thank you for your attention!